Science turns to seals to unlock mysteries under the ice cap

Japanese researchers in Antarctica are deploying Weddell seals equipped with high-tech head-mounted measuring devices to monitor the waters beneath the thick South Pole ice cap.

It allows team members from the National Institute of Polar Research (NIPR) and Hokkaido University to collect observational data in areas where it is unrealistic to even launch submersibles to collect data remotely during the winter season.

The practice also helps scientists trace the behavioral patterns and ecology of animals. Penguins are also used for research programs in Antarctica. So-called bio-logging involving sea creatures is attracting increasing attention from the scientific community as a way to measure water temperature, salinity and other marine conditions in areas where l he environment is extremely hostile.

Eight Weddell seals fitted with 580-gram devices on their heads to record water temperatures and salt levels were used for the project between March and September 2017, when researchers wintered at Japan’s Syowa station.

The project was supervised by Nobuo Kokubun, assistant professor of ecology at NIPR.

The information collected was relayed by satellite when the seals, which weigh an average of 326 kilograms, emerged from the water. Data was collected on seven of the seals.

It showed that one of the animals traveled 633 kilometers from Syowa station while another descended to a depth of 750 meters.

By analyzing the data, the researchers learned that warm seawater from the upper layer in the open ocean reaches Antarctica from the autumn season in March and April until the winter of that year. . The warmer water flowed under the ice, allowing seal populations to effectively catch their food.

“Antarctic krill and other creatures that serve as food (for seals) can be found in large numbers in the upper layer of the high seas,” Kokubun said. “They flowed in with the seawater, probably boosting biological productivity near the coast.”

Scientists from Hokkaido University, who study how ocean conditions change the amount of ice in Antarctica, looked at the impact of warm seawater on coastal areas.

“A good point is that seals can collect data in a wider area below the surface of thick ice, even during times when ships cannot be used for monitoring,” said Shigeru Aoki, associate professor of studying climate change at university.